Cross-country pipelines are extremely expensive to construct and must therefore be designed to retain their structural integrity for many years if the initial cost thereof is to be recouped. The exterior of the pipe is usually wrapped with a protective covering, which insulates the pipe from moisture and prevents the occurence of electrolysis, thereby greatly minimizing corrosion thereof. Should the outer surface of the pipe inadvertently contact a sharp object, such as a rock, repeated movement of the pipe due to thermal expansion will soon abrade away the covering and eventually expose the exterior metallic surfaces of the pipe to the deleterious effects of ambient. Subsequently, corrosive action and various other chemical reactions commence, and eventually the pipe must be uncovered and repaired. This is an expensive endeavor which can only be avoided by initially padding the entire outer peripheral surface of the pipeline with a suitable padding material. The padding material is usually comprised of sand or other earthen products, such as finely commuted limestone.
Heretofore it has been necessary to dig the pipeline ditch in such a manner that the excavated earth is placed in a coextensive line to one side thereof, and thereafter the opposed side of the ground contiguous thereto is scraped free of debris. Next, a continuous line of suitable padding material is spread on the cleansed area adjacent to the ditch so that earth handling vehicles, such as a maintainer, can subsequently "blade" a portion of the deposited padding material into the ditch. After the pipe has been positioned within the ditch where it is laid upon the padding material, the maintainer must again scrape another portion of the remaining padding material onto the top of the pipe. A generous portion of the padding material is deliberately left behind to minimize the probability of inadvertently scraping rocks and other harmful debris onto the top of the pipe.
The above-described prior operation is costly because it fails to utilize all of the padding material. Furthermore, the padding material is never uniformly distributed. Moreover, wind or rainstorms will often scatter the stored padding material, causing portions of the operation to be repeated.
Accordingly, it is desirable to have made available a padding machine within which padding can be stored for transporting, thereby enabling the machine to travel parallel and adjacent to a pipeline ditch in such a manner that padding material can be translocated directly from the vehicle into the ditch where the pipe is padded in a uniform and optimum manner.
This expedient eliminates the waste involved in the above-described prior art operation; and furthermore, more efficiently pads or insulates the pipe in a rapid and relatively inexpensive manner.